In a datacenter, network modules (e.g., Ethernet switches, Virtual Connect fabrics, etc.) may be linked to enhance connectivity and redundancy. Network modules may be linked in a variety of topologies according to various network protocols.
One popular example of a protocol commonly used for layer-2 networks is the spanning tree protocol or the rapid spanning tree protocol, which are standardized protocols. These protocols arrange nodes in the network in a tree topology, as their names suggest. These protocols may disable links to prevent loops and provide backup links in the spanning tree in case of node failure.
Another type of topology that may be implemented is a ring topology, which connects nodes in a ring. To prevent loops, a link may be disabled in the ring so packets are not continually forwarded in the ring, which can bring down the network. A protocol that may be used in the ring topology, which prevents loops, is Ethernet Ring Protection Switching (ERPS), which is standardized by the ITU Telecommunication Standardization Sector (ITU-T) under G.8032. Under the G.8032 standard, a node in the ring is selected as a ring protection link (RPL) owner. The RPL owner is responsible for disabling one of the links (i.e., blocking traffic on the link) to prevent a loop in the ring network. The disabled link is called the ring protection link (RPL).
Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts.